1. Field of the Invention
Exemplary embodiments of the invention relate to a light emitting device employing inorganic silicate-based luminescent substances as a radiation converter. The light emitting device can emit colored or white light by employing the luminescent substances, which can be used as a radiation converter for converting higher-energy primary radiation, for example ultra violet (UV) radiation or blue light, into a longer-wave visible radiation. The light emitting device comprising the luminescent conversion substances can be distinguished in particular for an improved temperature-dependent efficiency of the luminescence or quantum efficiency and for a longer life of the luminescent substances which can be responsible for the emission of the light produced. In particular, a high stability of the luminophores with respect to the radiation load occurring and with respect to the influence of atmospheric humidity and other environmental factors can be achieved.
2. Description of the Background
A light emitting device (LED) has been widely used for various applications, for example, indicators, display boards and display devices ever since the light emitting device can implement colors. White light can also has an applicability for general illumination. Since such a light emitting device provides high efficiency and long life span and is ecological, this has spawned the light emitting device to continuously develop for many applications.
To promote greater adoption, manufacturers effort to develop various methods for implementing colors including white light and techniques to dispose phosphors around a light emitting diode and to combine light emitted from the light emitting diode and light emitted from the phosphors is generally accepted to implement white light.
For example, europium-activated alkaline earth metal oxyorthosilicates of the general type Sr3SiO5:Eu have become known for use in LEDs emitting colored or white light, it also being possible completely or partly to replace the element strontium in these compounds by other alkaline earth metal ions.
However, acknowledged disadvantage of luminescent substances is that they have a comparatively short life under conditions of use. This is due in particular under the high moisture sensitivity of the europium-doped alkaline earth metal oxyorthosilicates.
Therefore, there is a need for an approach for reducing a substantial disadvantage which may cause completely prevent a technical applicability of the luminophores or at least limit the disadvantages to a considerable extent.